Simulation method of steering feedback torque

Abstract

The invention discloses a steering feedback torque simulation method, and relates to the technical field of automatic driving testing. According to the steering feedback torque simulation method provided by the invention, modeling description is carried out on physical characteristics of a steering feedback torque assembly by combining a steering angle of a steering wheel, steering angle speed input and vehicle motion state parameters, so that self-adaptive torque feedback aiming at different driving conditions is realized; meanwhile, delay compensation based on a Smith pre-estimation compensator is adopted, inherent pure lag delay of the system can be effectively eliminated, and calculation and feedback of steering feedback torque are more real-time and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of autonomous driving tests, and particularly to a method for simulating steering feedback torque. Background Art

[0002] With the rapid development of automotive technology, especially the increasing maturity of autonomous driving technology, simulation testing has gradually become an important means to verify and optimize autonomous driving systems. Compared with traditional real-vehicle testing, simulation testing based on a driving simulation system not only has the advantages of high efficiency and low cost, but also can simulate various complex driving conditions in a safe and controllable environment.

[0003] In a driving simulation system, the accurate simulation of steering feedback torque is an important factor affecting driving experience and simulation accuracy. The steering feedback torque simulation provides a perceptual feedback similar to that in the actual driving process to the driver by simulating the steering resistance torque of the vehicle under different working conditions.

[0004] In the process of implementing the present invention, the inventors found that the steering feedback torque simulation methods provided by related technologies have the following technical problems: The steering feedback torque simulation methods provided by related technologies often have problems such as communication delay, control motor delay, and model calculation delay, resulting in system response lag or instability, and further leading to system oscillation or divergence. These problems are particularly prominent when using data-driven models because the characteristics of data-driven models make it difficult to directly adapt to the dynamic requirements of real-time systems. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a method for simulating steering feedback torque, which effectively solves the delay problem of the steering feedback torque component in the driving simulation system through a delay compensation technology based on a Smith predictor compensator, and can significantly improve the real-time performance and stability of the system. The technical solution provided by the present invention is as follows: According to one aspect of an embodiment of the present invention, there is provided a method for simulating steering feedback torque, characterized in that the method for simulating steering feedback torque includes: S10: Obtain the input data, response data, and vehicle motion state parameter data corresponding to the steering feedback torque component in a real driving vehicle, where the input data includes steering wheel angle data and steering wheel angular velocity data, and the response data includes the steering feedback torque data and response duration data responded by the steering feedback torque module; S20: Model and describe the physical characteristics of the steering feedback torque assembly based on the input data, the response data, and the vehicle motion state parameter data to obtain the dynamic response model corresponding to the steering feedback torque assembly. The input of the dynamic response model is the torque received by the steering wheel, the output is the angular response of the steering wheel, and the input and output of the dynamic response model have time-domain characteristics; S30: Represent the dynamic response information of the steering feedback torque assembly in the time domain according to the transfer function corresponding to the dynamic response model, and identify the key parameters in the steering feedback torque assembly by using the least squares method to obtain the system inertia, damping, and torque transfer characteristics corresponding to the steering feedback torque assembly; S40: Construct a Smith predictor compensator corresponding to the steering feedback torque assembly according to the system inertia, damping, and torque transfer characteristics corresponding to the steering feedback torque assembly; S50: After performing feedforward compensation on the dynamic response model by using the Smith predictor compensator, obtain a steering feedback torque model with delay compensation, and use the steering feedback torque model to replace the steering feedback torque module in the steering feedback torque assembly.

[0006] Preferably, the steering feedback torque assembly includes a steering wheel, a feedback motor, an angle / torque sensor, and a steering feedback torque module; The shaft of the steering wheel is rigidly connected to the feedback motor through a coupling, and the steering wheel is used to receive the input data input by the driver; An angle / torque sensor is provided between the steering wheel and the feedback motor, and the angle / torque sensor is used to measure the angular and torque signals of the steering wheel in real time; The steering feedback torque module is used to calculate the steering feedback torque data corresponding to the steering wheel according to the steering wheel angle data and the steering wheel angular velocity data; The feedback motor is used to generate a feedback torque according to the steering feedback torque data calculated by the steering feedback torque module, and transmit the feedback torque to the steering wheel through the coupling.

[0007] Preferably, in the process of identifying the key parameters in the steering feedback torque assembly by using the least squares method according to the dynamic response information, an inertia-damping-stiffness model is used to represent the steering feedback torque model, and the system delay of the steering feedback torque assembly is simplified to a linear system by using the Pade approximation method.

[0008] Preferably, the second-order Pade approximation method is used for the system delay of the steering feedback torque assembly.

[0009] Preferably, the vehicle motion state parameter data includes vehicle speed, lateral acceleration, side acceleration, and yaw rate.

[0010] Compared with the prior art, a method for simulating steering feedback torque provided by the present invention has the following advantages: The method for simulating steering feedback torque provided by the present invention models and describes the physical characteristics of the steering feedback torque component by combining the steering angle of the steering wheel, the angular velocity input, and the vehicle motion state parameters, so as to achieve adaptive torque feedback for different driving conditions. At the same time, the delay compensation based on the Smith predictor compensator is adopted, which can effectively eliminate the inherent pure lag delay of the system, making the calculation and feedback of the steering feedback torque more real-time and accurate.

[0011] Furthermore, the present invention also proposes a system parameter identification method based on the least squares method, which can accurately identify the delay characteristics and mechanical characteristic parameters in the driving simulation system. This method can not only handle the inherent delay characteristics of the system, but also linearize the delay link through Pade approximation, greatly improving the simplification accuracy of the model. This delay compensation method based on accurate identification enables the system to maintain higher stability and responsiveness during delay compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention.

[0013] Figure 1 is a flowchart of a method for simulating steering feedback torque according to an exemplary embodiment of the present invention.

[0014] Figure 2 is a schematic diagram of a simulation system corresponding to a method for simulating steering feedback torque according to an exemplary embodiment of the present invention.

[0015] Figure 3 is a schematic diagram of the feedback effect of a method for simulating steering feedback torque according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings without creative efforts based on these drawings.

[0017] Figure 1It is a flowchart of a method for simulating a steering feedback torque shown according to an exemplary embodiment of the present invention. As Figure 1 shown, the method for simulating the steering feedback torque is characterized in that the method for simulating the steering feedback torque includes: S10: Obtain the input data, response data, and vehicle motion state parameter data corresponding to the steering feedback torque component in a real driving vehicle. The input data includes steering wheel angle data and steering wheel angular velocity data, and the response data includes the steering feedback torque data and response duration data responded by the steering feedback torque module.

[0018] Preferably, the steering feedback torque component includes a steering wheel, a feedback motor, an angle / torque sensor, and a steering feedback torque module; the shaft of the steering wheel is rigidly connected to the feedback motor through a coupling, and the steering wheel is used to receive the input data input by the driver; an angle / torque sensor is provided between the steering wheel and the feedback motor, and the angle / torque sensor is used to measure the angle and torque signals of the steering wheel in real time; the steering feedback torque module is used to calculate the steering feedback torque data corresponding to the steering wheel according to the steering wheel angle data and steering wheel angular velocity data; the feedback motor is used to generate a feedback torque according to the steering feedback torque data calculated by the steering feedback torque module and transmit the feedback torque to the steering wheel through the coupling.

[0019] In the hardware structure design of the present invention, real-time signal measurement is performed between the steering wheel and the feedback motor through an angle / torque sensor, which can adapt to driving simulator systems with different accuracy requirements. The feedback motor is rigidly connected to the steering wheel through a coupling, which also ensures the accuracy of torque transmission.

[0020] S20: Model and describe the physical characteristics of the steering feedback torque component according to the input data, the response data, and the vehicle motion state parameter data to obtain a dynamic response model corresponding to the steering feedback torque component. The input of the dynamic response model is the torque received by the steering wheel, and the output is the angular response of the steering wheel. Moreover, the input and output of the dynamic response model have time-domain characteristics.

[0021] The modeling in the embodiment of the present invention mainly describes the mechanical and electrical characteristics in the steering feedback torque component. Since the feedback motor is connected to the steering wheel through a rigid coupling and it is assumed that there is a high coaxiality between the motor shaft and the steering wheel shaft, the above system can be equivalent to an inertia-damping system. The specific characteristics are as follows: The input of the system is the torque applied by the driver; The output of the system is the angular response of the steering wheel, and this response will be affected by the delay of the mechanical structure and the control system.

[0022] It should be noted that the simulation method of the steering feedback torque provided by the related technology only calculates the steering feedback torque of the steering wheel that should be feedback output based on the steering wheel angle data and the steering wheel angular velocity data, while ignoring the influence of the current motion state of the vehicle on the steering feedback torque of the steering wheel. During the actual vehicle operation process, when the vehicle is moving slowly and at high speed, the steering feedback torque of the steering wheel should also be different. For example, in the slow motion state, the steering feedback torque of the steering wheel should be small, so that the driver can easily operate the steering wheel to turn and realize the flexible turning and lane change of the vehicle; in the high speed motion state, the steering feedback torque of the steering wheel should be large to avoid accidents such as vehicle rollover and skidding caused by the driver operating the steering wheel with too much force.

[0023] The embodiment of the present invention not only simulates the steering feedback torque based on the input such as the steering angle and angular velocity of the steering wheel, but also combines the motion state parameters of the vehicle, so as to realize the adaptive torque feedback for different driving conditions. This scheme of calculating the feedback torque by combining the dynamic driving conditions can significantly improve the simulation authenticity of the driving simulator and solve the problems of single feedback torque and inability to adaptively adjust according to different working conditions in the prior art.

[0024] Preferably, the vehicle motion state parameter data includes vehicle speed, lateral acceleration, lateral acceleration and yaw angular velocity.

[0025] In a feasible implementation manner, the calculation method of the steering feedback torque includes: The driver inputs a certain steering angle and angular velocity through the steering wheel. The steering feedback torque component obtains the current vehicle motion state parameters from the vehicle dynamics model, such as vehicle speed, lateral acceleration, yaw angular velocity, etc., and then combines these input information with the vehicle motion state to calculate the target steering torque. This target steering torque is used to control the feedback motor, so that the driver can feel the steering resistance torque corresponding to the vehicle motion state on the steering wheel.

[0026] S30: According to the transfer function corresponding to the dynamic response model, represent the dynamic response information of the steering feedback torque component in the time domain, and according to the dynamic response information, use the least square method to identify the key parameters in the steering feedback torque component, so as to obtain the system inertia, damping and torque transfer characteristics corresponding to the steering feedback torque component.

[0027] Due to the inherent delay in the feedback process of the system, it is necessary to separately identify the system delay parameters. The delay parameters mainly involve: the delay in the acquisition and transmission of the steering wheel angle signal, and the delay in the motor executing the target torque.

[0028] Preferably, in the process of identifying the key parameters in the steering feedback torque component by using the least squares method according to the dynamic response information, an inertia-damping-stiffness model is used to represent the steering feedback torque model, and the Pade approximation method is used to simplify the system delay of the steering feedback torque component into a linear system.

[0029] Preferably, the second-order Pade approximation method is used for the system delay of the steering feedback torque component.

[0030] The system parameter identification method based on the least squares method proposed by the present invention can accurately identify the delay characteristics and mechanical characteristic parameters (such as inertia, damping coefficient, etc.) in the driving simulation system. This method can not only handle the inherent delay characteristics of the system, but also linearize the delay link through Pade approximation, greatly improving the simplification accuracy of the model. This delay compensation method based on accurate identification enables the system to maintain higher stability and responsiveness during delay compensation.

[0031] S40: Construct a Smith predictor compensator corresponding to the steering feedback torque component according to the system inertia, damping, and torque transfer characteristics corresponding to the steering feedback torque component.

[0032] S50: After performing feedforward compensation on the dynamic response model by using the Smith predictor compensator, obtain a steering feedback torque model after delay compensation, and use the steering feedback torque model to replace the steering feedback torque module in the steering feedback torque component.

[0033] In a feasible implementation manner, the present invention can compensate for the negative impact of the pure lag part in the system by connecting a Smith predictor compensator in parallel with the dynamic response model of the steering feedback torque component, so as to offset the influence of system delay on the calculation and transmission of the feedback torque, making the dynamic response of the system close to that of a non-delay system.

[0034] Through the parallel predictor compensator, the delay link of the system is equivalent to an ideal closed-loop system without delay. The feedback torque felt by the driver on the steering wheel is more timely, avoiding the system instability problem caused by delay, enabling the system to maintain high stability when dealing with delay problems, and avoiding the divergence and oscillation phenomena caused by delay in traditional systems.

[0035] To better understand the simulation method of the steering feedback torque provided in the embodiments of the present invention, the system schematic diagram of the simulation system corresponding to the simulation method of the steering feedback torque proposed by the present invention is shown as Figure 2 shown.

[0036] To further illustrate the technical effects brought by the simulation method of the steering feedback torque provided by the embodiments of the present invention, a schematic diagram of the feedback effect of a simulation method of a steering feedback torque provided by the present invention is shown as Figure 3 shown. Among them, Figure 3 in (A) is a schematic diagram of the torque change, and (B) is a schematic diagram of the system feedback comparison of the steering feedback torque component before and after adopting the simulation method of the steering feedback torque provided by the present invention. Curve X corresponds to the system feedback broken line graph of the steering feedback torque component after adopting the simulation method of the steering feedback torque provided by the present invention, and curve Y corresponds to the system feedback broken line graph of the steering feedback torque component before adopting the simulation method of the steering feedback torque provided by the present invention. According to Figure 3 it can be seen that obviously, the system response of the steering feedback torque component is more stable after adopting the simulation method of the steering feedback torque provided by the present invention.

[0037] Compared with the prior art, a simulation method of a steering feedback torque provided by the present invention has the following advantages: The simulation method of the steering feedback torque provided by the present invention jointly models and describes the physical characteristics of the steering feedback torque component by combining the steering angle of the steering wheel, the angular velocity input, and the vehicle motion state parameters, so as to realize adaptive torque feedback for different driving conditions; at the same time, the delay compensation based on the Smith predictor compensator is adopted, which can effectively eliminate the inherent pure lag delay of the system, making the calculation and feedback of the steering feedback torque more real-time and accurate. Further, the present invention also proposes a system parameter identification method based on the least square method, which can accurately identify the delay characteristics and mechanical characteristic parameters in the driving simulation system. This method can not only process the inherent delay characteristics of the system, but also linearize the delay link through Pade approximation, greatly improving the simplification accuracy of the model. This delay compensation method based on accurate identification enables the system to maintain higher stability and responsiveness during delay compensation.

[0038] Although the present invention has been described in detail above with general descriptions, specific embodiments and experiments, it can be modified or improved on the basis of the present invention, which is obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

[0039] Other embodiments of the present invention will be readily apparent to those skilled in the art after considering the specification and practicing the invention herein. The present invention is intended to cover any variations, uses, or adaptations of the invention, which follow the general principles of the invention and include known common knowledge or conventional technical means in the technical field not disclosed by the present invention. It should be understood that the present invention is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for simulating steering feedback torque, characterized in that The simulation method of the steering feedback torque includes: S10: Obtain the input data, response data, and vehicle motion state parameter data corresponding to the steering feedback torque component in a real driving vehicle. The input data includes steering wheel angle data and steering wheel angular velocity data, and the response data includes the steering feedback torque data and response duration data responded by the steering feedback torque module. S20: Model and describe the physical characteristics of the steering feedback torque component according to the input data, the response data, and the vehicle motion state parameter data to obtain the dynamic response model corresponding to the steering feedback torque component. The input of the dynamic response model is the torque received by the steering wheel, and the output is the angular response of the steering wheel. Moreover, the input and output of the dynamic response model have time-domain characteristics. S30: Represent the dynamic response information of the steering feedback torque component in the time domain according to the transfer function corresponding to the dynamic response model, and identify the key parameters in the steering feedback torque component by using the least squares method to obtain the system inertia, damping, and torque transfer characteristics corresponding to the steering feedback torque component. S40: Construct a Smith predictor compensator corresponding to the steering feedback torque component according to the system inertia, damping, and torque transfer characteristics corresponding to the steering feedback torque component. S50: After performing feedforward compensation on the dynamic response model by using the Smith predictor compensator, obtain a steering feedback torque model with delay compensation, and use the steering feedback torque model to replace the steering feedback torque module in the steering feedback torque component.

2. The simulation method of the steering feedback torque according to claim 1, characterized in that The steering feedback torque component includes a steering wheel, a feedback motor, an angle / torque sensor, and a steering feedback torque module. The shaft of the steering wheel is rigidly connected to the feedback motor through a coupling, and the steering wheel is used to receive the input data input by the driver. An angle / torque sensor is provided between the steering wheel and the feedback motor, and the angle / torque sensor is used to measure the angular and torque signals of the steering wheel in real time. The steering feedback torque module is used to calculate the steering feedback torque data corresponding to the steering wheel according to the steering wheel angle data and the steering wheel angular velocity data. The feedback motor is used to generate a feedback torque according to the steering feedback torque data calculated by the steering feedback torque module and transmit the feedback torque to the steering wheel through the coupling.

3. The simulation method of the steering feedback torque according to claim 1, wherein, In the process of identifying the key parameters in the steering feedback torque component by using the least squares method according to the dynamic response information, an inertia-damping-stiffness model is used to represent the steering feedback torque model, and the Pade approximation method is used to simplify the system delay of the steering feedback torque component into a linear system.

4. The simulation method of the steering feedback torque according to claim 3, wherein The second-order Pade approximation method is used for the system delay of the steering feedback torque component.

5. The simulation method of the steering feedback torque according to claim 1, characterized in that The vehicle motion state parameter data includes vehicle speed, lateral acceleration, side acceleration, and yaw rate.

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